Adhesive sheet and layered product

Abstract

There are provided an adhesive sheet, exhibiting a specific peel strength and shear peel strength and being composed of a base material (A) comprising a fully aromatic polyimide film having a glass transition temperature of 200° C. or above and a thermal adhesive layer (C) comprising a fully aromatic polyamide having a glass transition temperature of 200-500° C., as well as a laminate composed of the sheet and a process for its production. Also provided is a method of release after treatment of the laminate composed of the adhesive sheet, to obtain a laminate having the target to-be-treated layer.

1 . An adhesive sheet composed of a base material (A) comprising a fully aromatic polyimide film having a glass transition temperature of 200° C. or above and a thermal adhesive layer (C) comprising a fully aromatic polyamide having a glass transition temperature of 200-500° C., the adhesive sheet being characterized in that, when the thermal adhesive layer (C) and base material (A) are laminated in that order on a silicon wafer adherend, either or both of the following conditions (a) and (b) are satisfied. 
 (a) A peel strength of 0.1-300 N/m at the interface between the thermal adhesive layer (C) and silicon wafer upon thermocompression bonding for 15 minutes at 300° C., 5.0-6.0 MPa.    (b) A shear peel adhesive strength of 1-1000 N/cm 2  at the interface between the thermal adhesive layer (C) and silicon wafer upon thermocompression bonding for 2 minutes at 300° C., 5.0-6.0 MPa.    
   
   
       2 . An adhesive sheet according to  claim 1 , characterized in that the linear thermal expansion coefficient is in the range of −10 ppm/° C. to +45 ppm/° C.  
   
   
       3 . An adhesive sheet according to  claim 1 , characterized in that the Young's modulus is in the range of 1.0-30 GPa.  
   
   
       4 . An adhesive sheet according to  claim 1 , characterized in that the base material (A) comprises a fully aromatic polyimide which has a constituent unit represented by the following formula (1):  
     
       
         
         
             
             
         
       
     
     wherein Ar 1  is 1,4-phenylene which may optionally contain a non-reactive substituent.  
   
   
       5 . An adhesive sheet according to  claim 1 , characterized in that the base material (A) comprises a fully aromatic polyimide which has 30-70 mole percent of a constituent unit represented by the following formula (1):  
     
       
         
         
             
             
         
       
     
     and 70-30 mole percent of a constituent unit represented by the following formula (2):  
     
       
         
         
             
             
         
       
     
     wherein Ar 2a  and Ar 2b  are each independently a C6-20 aromatic group optionally containing a non-reactive substituent.  
   
   
       6 . An adhesive sheet according to  claim 1 , characterized in that the adhesive sheet comprises a fully aromatic polyimide with an imide group density (eq./kg) of between 5.5 eq./kg and 6.9 eq./kg, according to the following formula (4).  
       Imide group density (eq./kg)=2×1000/[molecular weight per constituent unit]  (4)  
   
   
       7 . An adhesive sheet according to  claim 1 , characterized in that the thermal adhesive layer (C) comprises a fully aromatic polyamide which has a constituent unit represented by the following formula (3):  
     
       
         
         
             
             
         
       
     
     wherein Ar 3a  and Ar 3b  are each independently a C6-20 aromatic group optionally containing a non-reactive substituent.  
   
   
       8 . An adhesive sheet according to  claim 1 , characterized in that the thermal adhesive layer (C) comprises a fully aromatic polyamide which has a constituent unit represented by the following formula (3-1).  
     
       
         
         
             
             
         
       
     
   
   
       9 . An adhesive sheet according to  claim 1 , characterized in that the adhesive sheet is used for anchoring of a semiconductor in a semiconductor device fabrication process.  
   
   
       10 . A laminate (I) having an inorganic material (B) further laminated on the thermal adhesive layer (C) of an adhesive sheet according to  claim 1 , and therefore being composed of a base material (A) comprising a fully aromatic polyimide film, the thermal adhesive layer (C) and the inorganic material (B) laminated in that order.  
   
   
       11 . The laminate (I) according to  claim 10 , characterized in that the inorganic material (B) is a silicon wafer.  
   
   
       12 . The laminate (I) according to  claim 10 , characterized in that the laminate is used for anchoring of a semiconductor in a semiconductor device fabrication process.  
   
   
       13 . A process for production of the laminate (I) according to  claim 10 , characterized in that the base material (A) comprising a fully aromatic polyimide film is thermocompression bonded with the inorganic material (B) via the thermal adhesive layer (C) comprising a fully aromatic polyamide having a glass transition temperature of 200-500° C., at a temperature of 180-600° C. and a pressure of 0.001-1000 MPa for a period from 0.1 second to 1 hour.  
   
   
       14 . A laminate (II) composed of an organic protective layer (E) and a to-be-treated layer (D) further laminated on the base material (A) of the laminate (I) according to  claim 10 , and thus beingcomposed of a to-be-treated layer (D), an organic protective layer (E), a base material (A) comprising a fully aromatic polyimide film, a thermal adhesive layer (C) and an inorganic material (B), laminated in that order.  
   
   
       15 . The laminate (II) according to  claim 14 , characterized in that the to-be-treated layer (D) is a semiconductor board subjected to circuit part formation steps including introduction of impurities, and the inorganic material (B) is a holding substrate.  
   
   
       16 . A process for production of the laminate (II) according to  claim 14 , characterized in that the to-be-treated layer (D), organic protective layer (E), base material (A), thermal adhesive layer (C) and inorganic material (B) are laminated in that order and thermocompression bonded at a temperature of 180-600° C. and a pressure of 0.001-1000 MPa for a period from 0.1 second to 1 hour.  
   
   
       17 . A laminate (I′) which is composed of a base material (A) comprising a fully aromatic polyimide film with a glass transition temperature of 200° C. or above and an inorganic material (B), characterized in that when the base material (A) and a silicon wafer adherend are laminated, the base material (A) exhibits the following property: 
 (a′) A peel strength of 0.1-100 N/m at the interface between the base material (A) and silicon wafer upon thermocompression bonding for 15 minutes at 370° C., 5.0-6.0 MPa.    
   
   
       18 . The laminate (I′) according to  claim 17 , characterized in that the base material (A) comprises of a fully aromatic polyimide which has a constituent unit represented by the following formula (1):  
     
       
         
         
             
             
         
       
     
     wherein Ar 1  is 1,4-phenylene which may optionally contain a non-reactive substituent.  
   
   
       19 . The laminate (I′) according to  claim 18 , characterized in that the base material (A) comprises a fully aromatic polyimide which has 30-70 mole percent of a constituent unit represented by formula (1) above and 70-30 mole percent of a constituent unit represented by the following formula (2):  
     
       
         
         
             
             
         
       
     
     wherein Ar 2a  and Ar 2b  are each independently a C6-20 aromatic group optionally containing a non-reactive substituent.  
   
   
       20 . The laminate (I′) according to  claim 17 , characterized in that the base material (A) comprises fully aromatic polyimide having an imide group density (eq./kg) of between 5.5 eq./kg and 6.9 eq./kg, calculated according to the following formula (4).  
       Imide group density (eq./kg)=2×1000/[molecular weight per constituent unit]  (4)  
   
   
       21 . The laminate (I′) according to  claim 17 , characterized in that the inorganic material (B) is a silicon wafer.  
   
   
       22 . The laminate (I′) according to  claim 17 , characterized in that the laminate is used for anchoring of a semiconductor in a semiconductor device fabrication process.  
   
   
       23 . A process for production of the laminate (I′) according to  claim 17 , characterized in that the base material (A) comprising a fully aromatic polyimide film and the inorganic material (B) are thermocompression bonded at a temperature of 180-600° C. and a pressure of 0.001-1000 MPa for a period from 0.1 second to 48 hours.  
   
   
       24 . A laminate (II′) composed of an organic protective layer (E) and a to-be-treated layer (D) further laminated on the base material (A) of a laminate (I′) according to  claim 17 , and thus being composed of a to-be-treated layer (D), an organic protective layer (E), a base material (A) comprising a fully aromatic polyimide film and an inorganic material (B), laminated in that order.  
   
   
       25 . The laminate (II′) according to  claim 24 , characterized in that the to-be-treated layer (D) is a semiconductor board subjected to circuit part formation steps including introduction of impurities, and the inorganic material (B) is a holding substrate.  
   
   
       26 . A process for production of the laminate (II′) according to  claim 24 , characterized in that the to-be-treated layer (D), organic protective layer (E), base material (A) and inorganic material (B) are laminated in that order and thermocompression bonded at a temperature of 180-600° C. and a pressure of 0.001-1000 MPa for a period from 0.1 second to 48 hours.  
   
   
       27 . A process for production of a laminate (IV) characterized in that, after laminating and thermocompression bonding a to-be-treated layer (D), an organic protective layer (E), a base material (A) comprising a fully aromatic polyimide film having a glass transition temperature of 200° C. or above and an inorganic material (B) in that order, the exposed surface of layer D is subjected to thinning treatment to produce layer D′ and obtain a laminate (III) composed of layer D′, layer E, layer A and layer B, after which the interface between layer E and layer A is released to obtain a laminate (IV) composed of layer D′ and layer E.  
   
   
       28 . A process for production of a laminate (IV) according to  claim 27 , characterized in that the thermal adhesive layer (C) comprising a fully aromatic polyamide having a glass transition temperature of 200-500° C. exists between the base material (A) and the inorganic material (B).  
   
   
       29 . A process for production of a laminate (IV) according to  claim 27  or  28 , characterized in that the base material (A) comprises a fully aromatic polyimide which has a constituent unit represented by the following formula (1):  
     
       
         
         
             
             
         
       
     
     wherein Ar 1  is 1,4-phenylene which may optionally contain a non-reactive substituent.  
   
   
       30 . A process for production of a laminate (IV) according to  claim 27  or  28 , characterized in that the base material (A) comprises a fully aromatic polyimide which has 30-70 mole percent of a constituent unit represented by formula (1) above and 70-30 mole percent of a constituent unit represented by the following formula (2):  
     
       
         
         
             
             
         
       
     
     wherein Ar 2a  and Ar 2b  are each independently a C6-20 aromatic group optionally containing a non-reactive substituent.  
   
   
       31 . A process for production of a laminate (IV) according to  claim 28 , characterized in that the thermal adhesive layer (C) has a constituent unit represented by the following formula (3-1).  
     
       
         
         
             
             
         
       
     
   
   
       32 . A process for production of a laminate (IV) according to  claim 27  or  28 , wherein the to-be-treated layer (D) is a semiconductor board subjected to circuit part formation steps including introduction of impurities and the inorganic material (B) is a holding substrate, and the exposed surface of layer D is subjected to processing treatment whereby it is polished for thinning to form a thinned semiconductor board (layer D′), after which the interface between the organic protective layer (E) and the base material (A) is released to obtain a laminate for a semiconductor part comprising the semiconductor board (layer D′) and the organic protective layer (E).  
   
   
       33 . A process for production of a laminate (IV) according to  claim 27  or  28 , characterized in that the method for releasing the interface between layer E and layer A is a method of immersing the laminate in a liquid to allow the liquid to penetrate the interface between layer E and layer A, and then rapidly heating to above the boiling point of the liquid to gasify the liquid penetrated at the interface.  
   
   
       34 . A process for production of a laminate (IV) according to  claim 27  or  28 , characterized in that the method for releasing the interface between layer E and layer A is a method of immersing the laminate in water to allow the water to penetrate the interface between layer E and layer A, and then cooling to 0° C. or below to solidify the water penetrated at the interface for release.  
   
   
       35 . A process for production of a laminate (IV) according to  claim 27  or  28 , characterized in that the method for releasing the interface between layer E and layer A is a method of generating a temperature difference of 30-800° C. in the direction of thickness of the laminate to induce release of the interface between layer E and layer A.  
   
   
       36 . A process for production of a laminate (IV) according to  claim 27  or  28 , characterized in that the method for releasing the interface between layer E and layer A is a method of immersing the laminate in an alkali solution with a pH of 8-14 to allow the alkali solution to penetrate layer A to induce release of the interface between layer E and layer A.